The psyllid nymphs and adults feed on the underside of leaves, leaving the plant stunted and discoloured, with poor or little fruit growth. The psyllid also spreads a bacteria that causes Zebra Chip disease in some crops, like potatoes, which affects yields.
The wasp is a psyllid parasitoid which means it attaches to or within a single host, eventually killing it. It is a black, winged red-eyed wasp normally found in North America and Mexico.
The wasp lays its eggs on the surface of the psyllid nymphs. The eggs develop into larvae that feed on the nymphs, killing them.
Ray McMillan, EPA's acting general manager of hazardous substances and new organisms, says: "The parasitic wasp will be introduced as part of a pest management programme, in combination with other beneficial insects and chemical control strategies.
"The psyllid is a significant horticultural pest with wide-ranging effects on crops. However, once it's established, the wasp will create significant benefits for growers of potatoes, tomatoes and other food crops, and for our New Zealand economy."
The horticulture industry is currently worth $2 billion to the New Zealand domestic economy and $5 billion in exports.
"After considering potential risks and benefits to the New Zealand environment and the economy, the EPA approved this application without controls."
The application to introduce the wasp was made by Horticulture New Zealand Inc on behalf of a number of growers' industry groups under the Hazardous Substances and New Organisms (HSNO) Act 1996.
The EPA received 36 submissions on the application, with 32 in support, two neither supporting nor opposing, and two opposed. Seven submitters were heard at the hearing held on May 4.
The EPA's role is to decide on applications for the release of new organisms under the HSNO Act.
